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The IVA DPLL is not an essential DPLL for the functionality of a bootloader and is usually not configured (e.g. older u-boots configure it only if CONFIG_SYS_CLOCKS_ENABLE_ALL is enabled and u-boots newer than 2014.01 do not even have an option), and this results in incorrect operating frequencies when trying to use a DSP or IVAHD, whose root clocks are derived from this DPLL. Use the DT standard properties "assigned-clocks" and "assigned-clock-rates" to set the IVA DPLL clock rate and the rates for its derivative clocks at boot time to properly initialize/lock this DPLL. The DPLL will automatically transition into a low-power stop mode when the associated output clocks are not utilized or gated automatically. The reset values of the dividers M4 & M5 (functional clocks for DSP and IVAHD respectively) are identical to each other, but are different at each OPP. The reset values also do not match a specific OPP. So, the derived output clocks from the IVA DPLL have to be initialized as well to avoid initializing these divider outputs to incorrect frequencies. The clock rates are chosen based on the OPP100 values as defined in the OMAP4430 ES2.x Public TRM vAP, section "3.6.3.8.7 DPLL_IVA Preferred Settings". The DPLL locked frequency is 1862.4 MHz (value for DPLL_IVA_X2_CLK), so the dpll_iva_ck clock rate used is half of this value. Signed-off-by: Suman Anna <s-anna@ti.com> Acked-by: Tero Kristo <t-kristo@ti.com> Signed-off-by: Tony Lindgren <tony@atomide.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.